(a) Drivers, operators, or pilots of all equipment whether or not motorized in or on Research Center property, or within the scope of Research Center activity, shall operate in a careful and safe manner at all times and shall comply with the signals and directions of guards, special policemen, or other authorized individuals, and all posted traffic signs;

(b) The blocking of entrances, driveways, walks, railways, runways, loading platforms, or fire hydrants in or on Research Center property is prohibited;

(c) Except in emergencies, parking or landing in or on Research Center property in other than designated areas is not allowed without a permit. Parking without authority, parking in unauthorized locations or in locations reserved for other persons, or parking continuously in excess of ten hours without permission, or contrary to the direction of posted signs is prohibited. This section may be supplemented from time to time by the issuance and posting of specific traffic directives as may be required, and when so issued and posted such directives shall have the same force and effect as if made a part hereof;

(d) The operation of unlicensed gasoline powered vehicles is prohibited.